fix(@angular/build): address review feedback in sass directory and resolution caching

Qualify all imports with containing URL unless they start with 'pkg:' to prevent global collision of non-dot relative imports across different component directories.

Add a public clearCache() method to SassCompiler to clear the directory cache, and invoke it inside close().

Author: alan-agius4

packages/angular/build/src/tools/esbuild/stylesheets/sass-language.ts

@@ -122,9 +122,9 @@ async function compileString(
       importers: [
         {
           findFileUrl: (url, options) => {
-            const cacheKey = url.startsWith('.')
-              ? `${options.containingUrl?.href ?? ''}:${url}`
-              : url;
+            const cacheKey = url.startsWith('pkg:')
+              ? url
+              : `${options.containingUrl?.href ?? ''}:${url}`;
 
             return currentResolutionCache.getOrCreate(cacheKey, async () => {
               const result = await resolveUrl(url, options);

packages/angular/build/src/tools/sass/sass-service.ts

@@ -188,12 +188,19 @@ export class SassCompiler {
     return result;
   }
 
+  /**
+   * Clear the directory cache.
+   */
+  clearCache(): void {
+    this.#directoryCache.clear();
+  }
+
   /**
    * Shutdown the Sass compiler.
    * @returns A void promise that resolves when closing is complete.
    */
   async close(): Promise<void> {
-    this.#directoryCache.clear();
+    this.clearCache();
 
     if (this.#asyncCompilerPromise) {
       try {